Paper illustrates how researchers can boost flexural wave sensing

The research team created a new sensing technology platform by using adaptive metamaterial concepts. The platform creates a hybrid wave concentration mechanism through the material’s ability to further tune the signal and using electric signal amplification provided by a set of circuits connected to an array of sensors. Photos by Ryan Owens.

Piezoelectric sensors are used widely in a vast array of devices important to our everyday lives. A University of Missouri College of Engineering research team just developed a way to enhance their sensing capabilities multifold.

Guoliang Huang, an associate professor of mechanical and aerospace engineering, led an MU research team that published “Enhanced flexural wave sensing by adaptive gradient-index metamaterials” in Scientific Reports. The paper illustrates how the team developed active metamaterials to boost the elastic wave signals in large structures.

“We can tune the gradient to enhance the signal,” Huang said. “Eventually, when you change the gradient index, you amplify the signal. We made the signal two orders higher than the original signal.

Guoliang Huang discusses a graphic representation of how his new platform helps elastic wave signals cut through the noise thanks to greater amplification.

“Usually, when you’re talking about amplification, you’re only talking about electrical amplification. But when we did this technique, we made the perfect combination of mechanical and electrical amplification. And in this case, we can overcome the limitations.”

The research team created a new sensing technology platform by using adaptive metamaterial concepts. The platform creates a hybrid wave concentration mechanism through the material’s ability to further tune the signal and using electric signal amplification provided by a set of circuits connected to an array of sensors.

The work of the circuits and the composite metamaterial allows already-existing sensors to pick up weaker signals they couldn’t previously detect, amplifying the wave to cut through the surrounding noise. It’s the first such paper to illustrate how to use adaptive metamaterials to improve elastic wave sensing capabilities.

“This can be very useful to developing high-sensitivity sensing technology,” Huang said. “For example, you want to have a signal, but the signal-to-noise ratio is high. With this technique, we could do super sensing. We won’t amplify the noise, only the signal. Before, you had the problem of amplifying both the signal and noise.”

Piezoelectric sensors have a multitude of applications. They’re frequently used to detect structural damage in buildings, bridges, airplane wings and more. These sensors are used in structural health monitoring, aerospace and nuclear instrumentation, medical imaging and truss and cantilever components in bridges, among several other uses. The main purpose of the research is to develop a new active metamaterial through the use of electronically-controlled elements, which is funded by a grant from the U.S. Air Force Office of Scientific Research with program manager Byung-Lip (Les) Lee.

Huang and his team’s new platform improves these sensors by amplifying the signal, allowing the same amount of sensors to read even more data. Or, conversely, their platform can cut costs by allowing the fewer sensors to cover a larger structure and longer distance.

“Now we can, for any sensing transducers, by attaching our platform, make your signal amplification two orders higher,” Huang said.